I,R,P=input,range,print
def J():
	return map(int,I().split())
N=I()
t=""
for s in I():
	if s=="a" or s=="o":
		if t!="w" and t!="?":P("No"),exit(0)
	elif s=="w" or s=="n":
		if t=="w":P("No"),exit(0)
	elif s=="?":
		if t=="w":s="a"
	else:P("No"),exit(0)
	t=s
P(["No","Yes"][t!="w"])